Self-assembled hydrogel nanoparticles from curdlan derivatives: characterization, anti-cancer drug release and interaction with a hepatoma cell line (HepG2)

Rheology and gelation of aqueous carboxymethylated curdlan solution: Impact of the degree of substitution

Curdlan is a unique (1,3)-β-D-glucan with bioactivity and exceptional gelling properties. By chemical functionalization such as carboxymethylation, the physicochemical properties of curdlan can be significantly tailored. However, how the carboxymethylation extent of curdlan affects its rheology and gelation characteristics has yet to be fully understood. Herein, we investigated the impact of the degree of substitution (DS, ranging from 0.04 to 0.97) on the rheological and gelation behavior of carboxymethylated curdlan (CMCD). It was found that CMCD with DS below 0.20, resembling native curdlan, still retained its gelling capability. As the DS increased beyond 0.36, there was a significant increase in its water solubility instead of gelation, resulting in transparent solutions with steady/complex viscosities adhering to the Cox-Merz rule. Moreover, CMCD with high DS demonstrated the ability to undergo in-situ gelation in the presence of metal ions, attributed to the nonspecific electrostatic binding. Additionally, in vitro cytocompatibility testing showed positive compatibility across varying DS in CMCD. This research offers a holistic understanding of the viscosifying and gelling behaviors of CMCD with varying DS, thereby fostering their practical application as thickeners and gelling agents in fields ranging from food and biomedicine to cosmetics and beyond.

Nanomedicines for reversing immunosuppressive microenvironment of hepatocellular carcinoma

Although immunotherapeutic strategies such as immune checkpoint inhibitors (ICIs) have gained promising advances, their limited efficacy and significant toxicity remain great challenges for hepatocellular carcinoma (HCC) immunotherapy. The tumor immunosuppressive microenvironment (TIME) with insufficient T-cell infiltration and low immunogenicity accounts for most HCC patients' poor response to ICIs. Worse still, the current immunotherapeutics without precise delivery may elicit enormous autoimmune side effects and systemic toxicity in the clinic. With a better understanding of the TIME in HCC, nanomedicines have emerged as an efficient strategy to achieve remodeling of the TIME and superadditive antitumor effects via targeted delivery of immunotherapeutics or multimodal synergistic therapy. Based on the typical characteristics of the TIME in HCC, this review summarizes the recent advancements in nanomedicine-based strategies for TIME-reversing HCC treatment. Additionally, perspectives on the awaiting challenges and opportunities of nanomedicines in modulating the TIME of HCC are presented. Acquisition of knowledge of nanomedicine-mediated TIME reversal will provide researchers with a better opportunity for clinical translation of HCC immunotherapy.

An Updated Review on Advances in Hydrogel-Based Nanoparticles for Liver Cancer Treatment

More than 90% of all liver malignancies are hepatocellular carcinomas (HCCs), for which chemotherapy and immunotherapy are the ideal therapeutic choices. Hepatocellular carcinoma is descended from other liver diseases, such as viral hepatitis, alcoholism, and metabolic syndrome. Normal cells and tissues may suffer damage from common forms of chemotherapy. In contrast to systemic chemotherapy, localized chemotherapy can reduce side effects by delivering a steady stream of chemotherapeutic drugs directly to the tumor site. This highlights the significance of controlled-release biodegradable hydrogels as drug delivery methods for chemotherapeutics. This review discusses using hydrogels as drug delivery systems for HCC and covers thermosensitive, pH-sensitive, photosensitive, dual-sensitive, and glutathione-responsive hydrogels. Compared to conventional systemic chemotherapy, hydrogel-based drug delivery methods are more effective in treating cancer.

Development of Ulvan-Containing Liposomes as Antibacterial Drug Delivery Platforms

Liposomes, due to their safety profile and targeting ability, are among the most studied nanocarriers as antimicrobial delivery systems. However, due to lack of stability and the non-specific interaction of liposomes with cells and proteins, their use is relatively limited. Aiming to overcome these drawbacks, it was envisaged that incorporation of ulvan, a bioactive marine sulfated polysaccharide isolated from green algae, in liposomes could improve their physicochemical properties and overall stability. Thus, we initially studied the interactions of ulvan with neutral, negatively, and positively charged lipids using Differential Scanning Calorimetry and subsequently, based on the obtained results, we prepared the respective ulvan–containing neutral and charged liposomes, where ulvan interacts with both lipid chains and polar groups in the liposomal bilayer. In a further step, we entrapped in the liposomes fusidic acid, used as a model antibacterial drug, and proceeded with the evaluation of their antibacterial activity against Staphylococcus aureus. The physicochemical properties (size and ζ-potential), stability, morphology, and entrapment efficiency of the prepared liposomal formulations were determined.

Glycyrrhetinic acid-cyclodextrin grafted pullulan nanoparticles loaded doxorubicin as a liver targeted delivery carrier

In this work, glycyrrhetinic acid (GA)-β-cyclodextrin grafted pullulan (GCDPu) was synthesized and used to form nanoparticles for liver-specific drug delivery. GCDPu was characterized by Fourier transform infrared (FT-IR) and proton nuclear magnetic resonance (¹H NMR). The self-aggregated nanoparticles (GCDPu NPs) with a spherical dimension of about 200 nm were prepared and analyzed by dynamic light scattering (DLS), zeta potential, and transmission electron microscopy (TEM). Doxorubicin (DOX) was selected as an anti-cancer model drug, and the drug-loaded GCDPu NPs were prepared by the emulsion solvent evaporation method. Moreover, the drug encapsulation efficiency (LE%) and loading content (LC%) were determined. Slow DOX release from DOX/GCDPu NPs was confirmed. GCDPu NPs were cytocompatible with Bel-7404 cells and showed high cellular uptake according to the MTT assay, confocal laser scanning microscope (CLSM) and flow cytometry (FCM) results. Compared with free DOX, DOX/GCDPu NPs have exhibited a longer half-life time (t_1/2) and a larger area-under-the-curve (AUC). GCDPu NPs significantly increased DOX contents in the liver and decreased in heart and kidney. Furthermore, DOX/GCDPu NPs exhibited a better anticancer therapeutic effect on tumor-bearing mice. These findings suggest that GCDPu can serve a liver-specific drug delivery system.

Hydrogels for localized chemotherapy of liver cancer: a possible strategy for improved and safe liver cancer treatment

The systemic drug has historically been preferred for the treatment of the majority of pathological conditions, particularly liver cancer. Indeed, this mode of treatment is associated with adverse reactions, toxicity, off-target accumulation, and rapid hepatic and renal clearance. Numerous efforts have been made to design systemic therapeutic carriers to improve retention while decreasing side effects and clearance. Following systemic medication, local administration of therapeutic agents allows for higher 'effective' doses with fewer side effects, kidney accumulation, and clearance. Hydrogels are highly biocompatible and can be used for both imaging and therapy. Hydrogel-based drug delivery approach has fewer side effects than traditional chemotherapy and can deliver drugs to tumors for a longer time. The chemical and physical flexibility of hydrogels can be used to achieve disease-induced in situ accumulation as well as subsequent drug release and hydrogel-programmed degradation. Moreover, they can act as a biocompatible depot for localized chemotherapy when stimuli-responsive carriers are administrated. Herein, we summarize the design strategies of various hydrogels used for localized chemotherapy of liver cancer and their delivery routes, as well as recent research on smart hydrogels.

Exopolysaccharide synthesis repressor genes (exoR and exoX) related to curdlan biosynthesis by Agrobacterium sp

Curdlan is a neutral, water-insoluble, unbranched, linear β-(1,3)-glucan. This study explored the roles of exoR and exoX in curdlan biosynthesis in Agrobacterium sp. ATCC 31749. The microcapsule biosynthesis of ΔexoR strain was reduced, and the motility of this strain increased remarkably compared with the wild-type (WT) strain during the cell growth phase. The curdlan yields of ΔexoR and ΔexoX strains enhanced by 19% and 17%, and the glucose utilization increased by 12% and 11%, respectively, compared with the WT strain during batch fermentation. By contrast, the curdlan yields of exoR and exoX overexpression strains decreased by 28% and 33%, respectively. The gel strength produced by ΔexoR and exoX overexpression strains decreased compared with the WT strain. RT-qPCR analysis at the transcriptional level revealed that key genes in exopolysaccharide synthesis and central metabolic pathways were up-regulated in ΔexoX and ΔexoR strains during gel production. Metabolomics analysis of ΔexoR and ΔexoX mutants proved the rates of central metabolic and electron transport chain were accelerated.

Rheological properties and critical concentrations of a hyperbranched polysaccharide from Lignosus rhinocerotis sclerotia

The application of polysaccharides in the food industry mainly depends on their rheological properties and the polysaccharides in different concentration regions exhibit different rheological properties due to the interactions between polymer chains. Hence, this work investigated the concentration-dependent rheological behavior of Lignosus rhinocerotis polysaccharide (LRP) in water and determined the critical concentrations. The intrinsic viscosity of LRP was 378 ± 32 mL/g and the LRP exhibited more apparent shear-thinning behavior with increasing concentration. The LRP critical overlap and aggregation concentration in water was ~2.5 mg/mL, implicating the formation of hydrophobic regions may result from the aggregation and overlap between hyperbranched LRP molecules. The LRP/water system showed higher storage modulus than loss modulus with slight frequency dependence at the concentration of 15 mg/mL, exhibiting the structured liquid behavior. When the concentration increased from 10 mg/mL to 30 mg/mL, the compliance recovery percentage value increased from 58.51% to 92.30%, indicating the formation of a strong gel network in the LRP/water system. Furthermore, the micro-rheological test revealed that the LRP/water system exhibited a concentration-dependent increase in elasticity and viscosity and deterioration in fluidity.

The effect of carboxymethylation on the macromolecular conformation of the (1 → 3)-β -D-glucan of curdlan in water

The chain conformational change in curdlan during carboxymethylation was investigated using nuclear magnetic resonance (NMR), circular dichroism (CD) spectroscopy, and atomic force microscopy (AFM). The distributions of carboxymethyl substituents within anhydroglucose unit (AGU) of CMCD were found to follow the order of OH (6) > OH (4) > OH (2) for CMCD with a low DS and OH (6) > OH (2) > OH (4) for CMCD with relatively high DS. The increased carboxymethylation level induced the chain conformation transition of curdlan from triple helix to random coil in water. The DS of 0.25 was the critical value of chain conformation transition, below which CMCD chains were triple helices. For DS larger than 0.25, CMCD existed in the state of random coils. The intermolecular hydrogen bonding between C2 hydroxyls in AGU sustained the triple helical conformation and stiffness of the polymer chain, which weakened with the increase in DS.

Hydrogels Classification According to the Physical or Chemical Interactions and as Stimuli-Sensitive Materials

Hydrogels are attractive biomaterials with favorable characteristics due to their water uptake capacity. However, hydrogel properties are determined by the cross-linking degree and nature, the tacticity, and the crystallinity of the polymer. These biomaterials can be sorted out according to the internal structure and by their response to external factors. In this case, the internal interaction can be reversible when the internal chains are led by physicochemical interactions. These physical hydrogels can be synthesized through several techniques such as crystallization, amphiphilic copolymers, charge interactions, hydrogen bonds, stereo-complexing, and protein interactions. In contrast, the internal interaction can be irreversible through covalent cross-linking. Synthesized hydrogels by chemical interactions present a high cross-linking density and are employed using graft copolymerization, reactive functional groups, and enzymatic methods. Moreover, specific smart hydrogels have also been denoted by their external response, pH, temperature, electric, light, and enzyme. This review deeply details the type of hydrogel, either the internal structure or the external response. Furthermore, we detail some of the main applications of these hydrogels in the biomedicine field, such as drug delivery systems, scaffolds for tissue engineering, actuators, biosensors, and many other applications.

Polysaccharide conjugates surpass monosaccharide ligands in hepatospecific targeting - Synthesis and comparative in silico and in vitro assessment

Ligands with the polysaccharide headgroups have been recently reported by our group to possess enhanced interaction with asialoglycoprotein receptor (ASGPR) in silico as compared to ligands having galactose moieties. This enhanced interaction is a result of the polymer's backbone support in anchoring the ligand in a specific orientation within the bilayer. In this paper, we have attempted to provide an in vitro proof of concept by performing a comparative evaluation of polysaccharide and monosaccharide-based ligands. Docking was performed to understand interaction with ASGPR in silico. Agarose and galactose conjugates with behenic acid were synthesized, purified, and characterized to yield biocompatible hepatospecific ligands which were incorporated into nanoliposomes. Cellular internalization of these targeted liposomes was studied using confocal microscopy and flow cytometry. The toxicity potential was assessed in vivo. Results indicated that the polysaccharide-based ligand increased cellular uptake due to better interaction with the receptor as compared to ligand bearing a single galactose group. In addition to developing novel liver targeting ligands, the study also established proof of concept that has been suggested by earlier in silico investigations. The approach can be used to design targeting ligands and develop formulations with improved targeting efficacy.

Biomedical Applications of Bacteria-Derived Polymers

Plastics have found widespread use in the fields of cosmetic, engineering, and medical sciences due to their wide-ranging mechanical and physical properties, as well as suitability in biomedical applications. However, in the light of the environmental cost of further upscaling current methods of synthesizing many plastics, work has recently focused on the manufacture of these polymers using biological methods (often bacterial fermentation), which brings with them the advantages of both low temperature synthesis and a reduced reliance on potentially toxic and non-eco-friendly compounds. This can be seen as a boon in the biomaterials industry, where there is a need for highly bespoke, biocompatible, processable polymers with unique biological properties, for the regeneration and replacement of a large number of tissue types, following disease. However, barriers still remain to the mass-production of some of these polymers, necessitating new research. This review attempts a critical analysis of the contemporary literature concerning the use of a number of bacteria-derived polymers in the context of biomedical applications, including the biosynthetic pathways and organisms involved, as well as the challenges surrounding their mass production. This review will also consider the unique properties of these bacteria-derived polymers, contributing to bioactivity, including antibacterial properties, oxygen permittivity, and properties pertaining to cell adhesion, proliferation, and differentiation. Finally, the review will select notable examples in literature to indicate future directions, should the aforementioned barriers be addressed, as well as improvements to current bacterial fermentation methods that could help to address these barriers.

Beta-d-glucan-based drug delivery system and its potential application in targeting tumor associated macrophages

Use of polysaccharides as carriers in drug delivery system is a hot topic, especially those with specific recognition of immune cells, enabling them to be applied in targeting delivery system. β-d-glucans are naturally occurring non-digestible polysaccharides with immunomodulatory activities that have attracted increasing attention to serve as therapeutic agents or immune-adjuvants. Being able to be specifically recognized by immune cells like macrophages, β-d-glucans can be developed as promising carriers for targeting delivery with stability, biocompatibility and specificity when applied in immunotherapy. Targeting tumor associated macrophages (TAMs) is an emerging strategy for cancer immunotherapy since it exerts anti-cancer effects based on modulating body immunity in tumor microenvironment (TME). This new strategy does not require high concentration of drugs to kill cancer cells directly and lessen tumor recurrence by creating unique immune memory for malignant cells. In this review, construction strategies of polysaccharide-based drug delivery system of three types of β-d-glucan including non-yeast and yeast β-d-glucans as well as hyper-branched β-d-glucan are discussed with reference to their branching characteristics and conformation. The applications of these β-d-glucans as nano-carrier for drug delivery targeting TAMs are also discussed.

Effect of Gelation Temperature on the Molecular Structure and Physicochemical Properties of the Curdlan Matrix: Spectroscopic and Microscopic Analyses

In order to determine the effect of different gelation temperatures (80 °C and 90 °C) on the structural arrangements in 1,3-β-d-glucan (curdlan) matrices, spectroscopic and microscopic approaches were chosen. Attenuated total reflection Fourier transform infrared spectroscopy (ATR FT-IR) and Raman spectroscopy are well-established techniques that enable the identification of functional groups in organic molecules based on their vibration modes. X-ray photoelectron spectroscopy (XPS) is a quantitative analytical method utilized in the surface study, which provided information about the elemental and chemical composition with high surface sensitivity. Contact angle goniometer was applied to evaluate surface wettability and surface free energy of the matrices. In turn, the surface topography characterization was obtained with the use of atomic force microscopy (AFM) and scanning electron microscopy (SEM). Described techniques may facilitate the optimization, modification, and design of manufacturing processes (such as the temperature of gelation in the case of the studied 1,3-β-d-glucan) of the organic polysaccharide matrices so as to obtain biomaterials with desired characteristics and wide range of biomedical applications, e.g., entrapment of drugs or production of biomaterials for tissue regeneration. This study shows that the 1,3-β-d-glucan polymer sample gelled at 80 °C has a distinctly different structure than the matrix gelled at 90 °C.

Does Pharmacodynamics of Drugs Change After Presenting them as Nanoparticles Like their Pharmacokinetics?

:

Nowadays, the breakthrough in different medical branches makes it feasible to designate new methods of drug delivery to achieve the most cost-effective and the least unpleasant consequenceimposing solutions to overcome a wide range of diseases.

:

Nanoparticle (NP) drugs entered the therapeutic system, especially in cancer chemotherapy. These drugs are quite well-known for two traits of being long-acting and less toxic. For a long time, it has been investigated how NPs will change the kinetics of drugs. However, there are a few studies that inclined their attention to how NPs affect the dynamics of drugs. In this review, the latter point will mainly be discussed in an example-based manner. Besides, other particular features of NPs will be briefly noted.

:

NPs are capable of affecting the biologic system as much as a drug. Moreover, NPs could arise a wide variety of effects by triggering their own receptors. NPs are able to change a receptor function and manipulate its downstream signaling cascade.

Nanoparticle-mediated in vitro delivery of E4orf1 to preadipocytes is a clinically relevant delivery system to improve glucose uptake

OBJECTIVE

Impaired glycemic control is a common comorbidity of obesity. E4orf1(E4), an adenovirus-derived protein, reduces the activity of insulin receptor substrate (IRS), yet activates Akt and promotes the membrane translocation of GLUT4, resulting in better glycemic control in mice. To develop a clinically suitable delivery system, here we constructed and tested liposome nanoparticles (NP), to deliver E4 to preadipocytes.

METHODS

Glutathione-S-transferase (GST)-tagged E4 was encapsulated in Rhodamine-phosphatidylethanolamine (PE)-tagged soy-phosphatidylcholine-NP. The NP were characterized. Preadipocytes were treated with free E4, E4 containing NP (E4 NP) or E4-free NP (void NP).

RESULTS

For void and E4 NP, the average size was ~150 and 130 nm, PDI was ~0.25 and 0.27, and Zeta potential was -23 and -25, respectively. The average encapsulation efficiency (EE) was ~50%. Cells treated with E4 showed maximum GST expression and Rhodamine signals at 24 h. The presence of E4 in cells was confirmed at 24, 48, and 72 h. At 72 h after exposure, E4 NP significantly decreased pTyr-IRS, yet increased pAkt protein abundance, membrane translocation of GLUT4, and glucose uptake, compared with cells treated with void NP. Free E4 (without NP) had no effect.

CONCLUSIONS

NP-mediated delivery of E4 promotes glucose uptake in preadipocytes. The next step is to test the efficacy of this clinically compatible delivery approach in vivo.

Colloidal hydroxyethyl starch for tumor-targeted platinum delivery

Cis-platinum has been widely used as a first-line chemotherapy agent in clinics for more than 40 years. Although considerable efforts have been expended for developing platinum-based nano drug delivery systems (NDDS) to resolve the problems of low water solubility, short half-life, and severe side effects of cis-platinum, it remains challenging to apply these nanoplatforms to cancer treatments in clinics on account of the issues related to safety, complex fabrication procedures, and limited cellular uptake. Herein, we constructed a novel cis-platinum delivery system with hydroxyethyl starch (HES), which is a semisynthetic polysaccharide that has been used worldwide as colloidal plasma volume expanders (PVE) in clinics for several decades. By combining TEM, AFM, and DLS, we have found that HES particles are colloidal nanoparticles in solution, with diameters ranging from 15 to 40 nm as a function of molecular weight. We further revealed that HES adopted a hyperbranched colloidal structure with rather compact conformation. These results demonstrate that HES is a promising nanocarrier to deliver drug molecules. Taking advantage of the poly-hydroxyl sites of HES, we constructed a novel HES-based cis-platinum delivery nanoplatform. HES was directly conjugated with cis-platinum prodrug via an ester bond and decorated with an active targeting molecule, lactobionic acid (LA), contributing toward higher in vitro antitumor activity against hepatoma carcinoma cells as compared to cis-platinum. These results have significant implications for the clinically used plasma volume expander-HES and shed light on the clinical translation of HES-based nano drug delivery systems.

Assembly of Conducting Polymer and Biohydrogel for the Release and Real-Time Monitoring of Vitamin K3

In this work, we report the design and fabrication of a dual-function integrated system to monitor, in real time, the release of previously loaded 2-methyl-1,4-naphthoquinone (MeNQ), also named vitamin K3. The newly developed system consists of poly(3,4-ethylenedioxythiophene) (PEDOT) nanoparticles, which were embedded into a poly-γ-glutamic acid (γ-PGA) biohydrogel during the gelling reaction between the biopolymer chains and the cross-linker, cystamine. After this, agglomerates of PEDOT nanoparticles homogeneously dispersed inside the biohydrogel were used as polymerization nuclei for the in situ anodic synthesis of poly(hydroxymethyl-3,4-ethylenedioxythiophene) in aqueous solution. After characterization of the resulting flexible electrode composites, their ability to load and release MeNQ was proven and monitored. Specifically, loaded MeNQ molecules, which organized in shells around PEDOT nanoparticles agglomerates when the drug was simply added to the initial gelling solution, were progressively released to a physiological medium. The latter process was successfully monitored using an electrode composite through differential pulse voltammetry. The fabrication of electroactive flexible biohydrogels for real-time release monitoring opens new opportunities for theranostic therapeutic approaches.

Exopolysaccharide-Derived Carbon Dots for Microbial Viability Assessment

Fluorescent dye staining combined with fluorescence microscopy or flow cytometry is becoming a routine way to monitor microorganism viability that is necessary for food safety, antibiotic development, and human health. However, the conventional live/dead assay dyes suffer from high cost, inconvenient staining steps, and high cytotoxicity, which is urgently needed to overcome. Herein, cheap carbon dots, CDs-EPS605, were reported to successfully assess microbial viability in a convenient way with neglectable cytotoxicity. The fluorescent N-doped CDs-EPS605 could be facilely prepared from bacterial amino exopolysaccharide (EPS) by one-step hydrothermal carbonization, which is cost-effective and sustainable. The negatively charged CDs-EPS605 consisted of C, H, O, N, P, and S, and featured various functional groups, including -COOH, -OH, -CONH-, and -NH2. CDs-EPS605 were observed to sensitively and selectively stain dead microorganisms instead of live ones to enable discrimination of live/dead microorganisms. The labeling method with CDs-EPS605 did not require protection from light, or washing, which is convenient. Additionally, CDs-EPS605 displayed better photostability and much less cytotoxicity compared to the commercial counterpart. Altogether, CDs-EPS605 represent a simple, yet powerful staining agent for microbial viability assessment, and at the same time enrich the current applications of microbial EPS.

Hydrophobic interaction mediated coating of pluronics on mesoporous silica nanoparticle with stimuli responsiveness for cancer therapy

In this research, a novel method was used to successfully stably coat Pluronic P123 on mesoporous silica nanoparticles (MSNs). Co-constructing a drug delivery system (DDS) with P123 and MSNs has not been previously reported. In this DDS, the coating of P123 was realized through a hydrophobic interaction with octadecyl chain-modified MSNs. The experiments found only Pluronic with an appropriate ratio of hydrophilic and lipophilic segments could keep the nanoassemblies stable. For comparison, nanoassemblies consisting of P123 and octadecyl chain-modified MSNs with or without a disulfide bond were prepared, which were denoted as PSMSNs and PMSNs, respectively. The disulfide bond was expected to endow the system with redox-responsiveness to enhance the therapeutic effect meanwhile decreasing the toxicity. A series of experiments including characterization of the nanoparticles, in vitro drug release, cell uptake and cellular drug release, in vitro cytotoxicity, cell migration and biodistribution of the nanoparticles were carried out. Compared with the PMSNs, PSMSNs displayed a redox-responsive drug release property not only in in vitro release text, but also on the cellular level. In addition, the cell migration experiments proved that the coating of P123 endowed the system with the ability of anti-metastasis. The accumulation of P123 in the tumor was enhanced after coating the MSNs by virtue of the 'EPR' effect of nanoparticles compared with the solution form.

Co-delivery of doxorubicin and shRNA of Beclin1 by folate receptor targeted pullulan-based multifunctional nanomicelles for combinational cancer therapy

Doxorubicin (DOX) is a widely-used effective antitumor agent. However, its clinical application is limited due to its side effects including anti-apoptotic defense of cancer cells caused by DOX-induced autophagy and deleterious effects in normal tissues. Therefore, in this study, a new folate (FA)-decorated amphiphilic bifunctional pullulan-based copolymer (named as FPDP) was developed as an efficient nano-carrier for the co-delivery of DOX and short hairpin RNA of Beclin1, a pivotal autophage-related gene, to enhance the anticancer effect of DOX by the blockade of the Beclin1 protein mediated autophagy process. In FPDP molecules, pullulan was modified with lipophilic desoxycholic acid for the formation of micelles, the introduced low molecular weight (1 kDa) branched polyethylenimine (PEI) was for shBeclin1 delivery, and folate (FA) was employed as the tumor-targeting group. FPDP micelles demonstrated an average diameter of 161.9 nm, good biocompatibility, applicable storage stability, excellent loading capacities for both DOX and shBeclin1 and a sustained drug release profile. In vitro cell culture experiments demonstrated that the uptake amount of FPDP/DOX micelles in folate receptor positive (FR⁺) HeLa cells was more than that in folate receptor negative (FR⁻) HepG2 cells, leading to significantly higher cytotoxicity against FR⁺ HeLa cells. The simultaneous co-delivery of shBeclin1 and DOX to HeLa cells with FPDP micelles led to efficient reduction in the expression level of Beclin1 as well as synergistic cell apoptotic induction. Furthermore, in vivo studies revealed superior antitumor efficacy of tumor-targeted FPDP/DOX/shBeclin1 in comparison with non-FR-targeted PDP micelles and free DOX. These results highlighted that co-delivery of DOX and shRNA of Beclin1 with FPDP micelles has the potential to overcome the limitations of DOX in clinical cancer therapy.

New folate receptor targeted nano-micelles enhanced the anticancer effect of doxorubicin by shBeclin1 with the blockade of the autophagy process.

Preparation and in vitro characterization of retinoic acid-loaded poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) micelles

In order to achieve the controlled release of all-trans-retinoic acid (ATRA), poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) (PCL-PEG-PCL) copolymer with average molecular weight of 5.34 kDa was synthesized. The nanosized micelles were prepared from copolymer by nano-precipitation method. Critical association concentration (CAC) of micelles was measured by fluorimetry and results indicated low CAC value of micelles (1.9 × 10^-3 g/L). ATRA was encapsulated in the core of micelles using different ratios of drug to copolymer. In the case of 10% drug to polymer ratio, more than 80% of the drug was released within 3 days, whereas for ratio of 2% more than 90% of the drug was released within 3 h. The cytotoxic study performed by MTT assay showed that H1299 survival percent decreased significantly (P ≤ 0.05) after exposure to drug-loaded micelles, while no proliferation inhibition effect was observed by either free ATRA or blank PCL-PEG-PCL micelles.

Use of FT-IR, FT-Raman and thermal analysis to evaluate the gel formation of curdlan produced by Agrobacterium sp. IFO 13140 and determination of its rheological properties with food applicability

Curdlan is a linear polysaccharide composed of glucose units joined by β-(1,3) bonds that possesses unique gelation properties. This study aimed to characterize the structure and evaluate the gelling properties of curdlan produced by Agrobacterium sp. IFO 13140 and its gels, as well as apply it in food. FT-Raman analysis highlighted the structural changes that occurred during the formation of gels, with variations related to the hydrogen bonds and hydrophobic interactions, which occur with the formation of the low-set and high-set gels, respectively. Rheological analysis showed that the pre-gelled commercial curdlan and the curdlan produced by Agrobacterium sp. IFO 13140 differed in terms of gelation properties, which depends of the degree of polymerization of the polysaccharide, but when applied to pasta products, both improved the texture parameters. The curdlan gels were found to have great potential as gelling agents to improve texture, water retention capacity and stability of food products.

Functionalization of Carbon Nanomaterial Surface by Doxorubicin and Antibodies to Tumor Markers

The actual task of oncology is effective treatment of cancer while causing a minimum harm to the patient. The appearance of polymer nanomaterials and technologies launched new applications and approaches of delivery and release of anticancer drugs. The goal of work was to test ultra dispersed diamonds (UDDs) and onion-like carbon (OLCs) as new vehicles for delivery of antitumor drug (doxorubicin (DOX)) and specific antibodies to tumor receptors. Stable compounds of UDDs and OLCs with DOX were obtained. As results of work, an effectiveness of functionalization was 2.94 % w/w for OLC-DOX and 2.98 % w/w for UDD-DOX. Also, there was demonstrated that UDD-DOX and OLC-DOX constructs had dose-dependent cytotoxic effect on tumor cells in the presence of trypsin. The survival of adenocarcinoma cells reduced from 52 to 28 % in case of incubation with the UDD-DOX in concentrations from 8.4-2.5 to 670-20 μg/ml and from 72 to 30 % after incubation with OLC-DOX. Simultaneously, antibodies to epidermal growth factor maintained 75 % of the functional activity and specificity after matrix-assisted pulsed laser evaporation deposition. Thus, the conclusion has been made about the prospects of selected new methods and approaches for creating an antitumor agent with capabilities targeted delivery of drugs.

Amphiphilic poly-N-vynilpyrrolidone nanoparticles: Cytotoxicity and acute toxicity study

The aim of the present study was to evaluate the cytotoxicity against MCF-7 cells and acute intraperitoneal toxicity of amphiphilic poly-N-vinylpyrrolidone nanoparticles to confirm possibility of their application for creation of novel drug delivery systems. The effect of cellular uptake of polymeric nanoparticles on human cancer cell line MCF-7 cells was investigated by MTT assay. MTT analysis showed that tested amphiphilic polymers were essentially non-toxic. In acute toxicity studies, LD50 and other toxicity indexes were evaluated, under which no deaths or treatment related complications were observed even in high concentration treatment for 14 days of experiment. For histological analysis, organs of the animals were weighed and examined. No animal died during the study and no significant changes have been observed regarding body weight, feed consumption, organ weight or histological data. Obtained results show that amphiphilic poly-N-vinylpyrrolidone nanoparticles possessed no toxicity against cells and in animals after intraperitoneal administration. Thus, amphiphilic PVP nanoparticles demonstrate high potential as carriers for novel high-effective drug delivery systems.

New progress and prospects: The application of nanogel in drug delivery

Nanogel has attracted considerable attention as one of the most versatile drug delivery systems especially for site-specific and/or time-controlled delivery of bioactive agents owing to their combining features of hydrogel and nanoparticle. Physically synthesized nanogels can offer a platform to encapsulate various types of bioactive compounds, particularly hydrophobic drugs and biomacromolecules, but they have poor mechanical stability, whereas nanogels prepared by chemical cross-link have a wider application and larger flexibility. As an ideal drug-delivery carrier, nanogel has excellent drug loading capacity, high stability, biologic consistence and response to a wide variety of environmental stimuli. Nowadays, targeting and response especially multi-response of the nanogel system for drug delivery have become an issue in research. And the application study of nanogels mainly focuses on antitumor agents and proteins. This review focuses on the formation of nanogels (physical and chemical cross-linking) and their release behavior. Recent application of nanogels is also discussed.

Recapitulating the Tumor Ecosystem Along the Metastatic Cascade Using 3D Culture Models

Advances in cancer research have shown that a tumor can be likened to a foreign species that disrupts delicately balanced ecological interactions, compromising the survival of normal tissue ecosystems. In efforts to mitigate tumor expansion and metastasis, experimental approaches from ecology are becoming more frequently and successfully applied by researchers from diverse disciplines to reverse engineer and re-engineer biological systems in order to normalize the tumor ecosystem. We present a review on the use of 3D biomimetic platforms to recapitulate biotic and abiotic components of the tumor ecosystem, in efforts to delineate the underlying mechanisms that drive evolution of tumor heterogeneity, tumor dissemination, and acquisition of drug resistance.